TUESDAY, July 15, 2014 (HealthDay News) -- People who've had a stroke face a significantly higher risk of serious complications if they have an elective surgery during the nine months following their stroke, according to a new Danish study.

And, the sooner it is after the stroke, the greater the risk.

The odds of another stroke, heart attack or cardiovascular death are 14 times higher for people who have elective surgery within three months of a stroke, the study found. If you wait until between three and six months post-stroke, the odds drop to about five times as high compared to someone who hasn't had a stroke. At six to 12 months after a stroke, the odds of a serious outcome are about three times higher versus those who've never had a stroke.

About nine months after a stroke, the risks from surgery are still elevated but have stabilized, according to the study's lead author, Dr. Mads Jorgensen, a research assistant in the department of cardiology at the University of Copenhagen in Denmark.

"Even surgeries traditionally considered low-risk are associated with a risk at least as high as intermediate- and high-risk surgery. Thus no surgery may be considered safe in this group of patients with a history of stroke," he said.

The report appears in the July 16 issue of the Journal of the American Medical Association.

Dr. Ralph Sacco, chair of neurology at the University of Miami Miller School of Medicine and author of an accompanying journal editorial, said, "Stroke patients are always at increased risk for a recurrent stroke or other heart events, particularly after surgery."

The increased risk of problems could be the result of stopping anti-clotting drugs, such as aspirin and warfarin, before surgery or changes in the patient's blood pressure or clotting during surgery, he said.

"We may not be able to avoid surgery, but we should find ways to do it more safely, especially among survivors of stroke," Sacco said.

Dr. Jay Yasen, director of the stroke service at Winthrop-University Hospital in Mineola, N.Y., added, "This study raises further concerns, and should give pause to surgeons who are planning elective surgeries."

Yasen suggested, "Patients who need elective surgery and have a history of stroke should have a discussion with their neurologist and surgeon concerning the timing of both the surgery and withholding of anti-clotting medications."

For the study, Jorgensen's team collected data on more than 480,000 patients who had non-heart elective surgery from 2005 to 2011. Of those, just over 7,100 had a history of stroke.

The investigators found that patients who had a stroke prior to having surgery were more likely to have another stroke, a heart attack or die in the month after surgery than those who hadn't had a stroke.

In fact, per 1,000 people having elective surgery, about 54 stroke patients were likely to have one of these events, compared with about 4 of those who didn't have a stroke.

Overall, the researchers found the risk of dying in the 30 days following surgery was increased 1.8-fold, and the risk of another stroke or a heart attack was increased 4.8-fold for people who'd had a past stroke, no matter how long it had been since the stroke, the study found.

Dr. Alexander Ortiz, director of neuro-endovascular surgery and stroke at Lenox Hill Hospital in New York City, said, "Patients should wait at least nine months after a stroke before having elective surgery. If it's an emergency, then, obviously, the rule will be waived."